自学教程：C++ swapBuffers函数代码示例

void GraspTest::displayCallback(void) {    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 	if (m_dynamicsWorld)		m_dynamicsWorld->debugDrawWorld();//	drawLimit();	renderme();    glFlush();    swapBuffers();}

void StelAppGraphicsWidget::paint(QPainter* painter, const QStyleOptionGraphicsItem*, QWidget*){	// Don't even try to draw if we don't have a core yet (fix a bug during splash screen)	if (!stelApp || !stelApp->getCore() || !doPaint)		return;		StelPainter::setQPainter(painter);	if (useBuffers)	{		StelPainter::makeMainGLContextCurrent();		initBuffers();		backgroundBuffer->bind();		QPainter* pa = new QPainter(backgroundBuffer);		StelPainter::setQPainter(pa);		// If we are using the gui, then we try to have the best reactivity, even if we need to lower the fps for that.		int minFps = StelApp::getInstance().getGui()->isCurrentlyUsed() ? 16 : 2;		while (true)		{			bool keep = paintPartial();			if (!keep) // The paint is done			{				delete pa;				backgroundBuffer->release();				swapBuffers();				break;			}			double spentTime = StelApp::getTotalRunTime() - previousPaintFrameTime;			if (1. / spentTime <= minFps) // we spent too much time			{				// We stop the painting operation for now				delete pa;				backgroundBuffer->release();				break;			}		}		Q_ASSERT(!backgroundBuffer->isBound());		Q_ASSERT(!foregroundBuffer->isBound());		// Paint the last completed painted buffer		StelPainter::setQPainter(painter);		viewportEffect->paintViewportBuffer(foregroundBuffer);	}	else	{		while (paintPartial()) {;}	}	StelPainter::setQPainter(NULL);	previousPaintFrameTime = StelApp::getTotalRunTime();}

void createWindow(char* windowName, int boardSize, MouseListener l) {    int windowSize = 2*BOARD_PADDING + boardSize * TILE_SIZE;    initwindow(windowSize, windowSize, windowName);    setbkcolor(LIGHTGRAY);    clearScreen();    swapBuffers();    mouseClickListener.l = l;    // register mouse listeners    registermousehandler(WM_LBUTTONDOWN, mouseDown);    registermousehandler(WM_LBUTTONUP, mouseUp);    registermousehandler(WM_MOUSEMOVE, mouseMove);}

    //-----------------------------------------------------------------------    void RenderTarget::update(bool swap)    {        OgreProfileBeginGPUEvent("RenderTarget: " + getName());        // call implementation        updateImpl();        if (swap)        {            // Swap buffers            swapBuffers();        }        OgreProfileEndGPUEvent("RenderTarget: " + getName());    }

    void BulletOpenGLViewer::displayCallback()    {        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);        if (m_dynamicsWorld)        {            m_dynamicsWorld->debugDrawWorld();        }        renderme();        glFlush();        swapBuffers();    }

	void SceneDisplayerWidget::paintGL()	{		if(sceneDisplayer!=nullptr)		{			sceneDisplayer->paint();		}else		{			glClear(GL_COLOR_BUFFER_BIT);			glClearColor(0.1f, 0.05f, 0.1f, 1.0f);		}		swapBuffers();		update();	}

void GLWidget::Draw(){    setRotate();    GLfloat length = 2.0;    int i,j,k;    glPushMatrix();    for( i = -1; i <= 1; i++)        for( j = -1; j <= 1; j++)            for( k = -1; k <= 1; k++)            {                glPushMatrix();                glTranslatef(length*i*1.05,length*j*1.05,length*k*1.05);                cube(length);                glPopMatrix();            }    glPopMatrix();    swapBuffers();    /////////////////////////////////    /*    glPushMatrix();    glBegin( GL_QUADS );       glColor3f( 0.0, 1.0, 0.0 );       glVertex3f(  1.0,  1.0, -1.0 );       glVertex3f( -1.0,  1.0, -1.0 );       glVertex3f( -1.0,  1.0,  1.0 );       glVertex3f(  1.0,  1.0,  1.0 );glColor3f( 1.0, 0.5, 0.0 );       glVertex3f(  1.0, -1.0,  1.0 );       glVertex3f( -1.0, -1.0,  1.0 );       glVertex3f( -1.0, -1.0, -1.0 );       glVertex3f(  1.0, -1.0, -1.0 );glColor3f( 1.0, 0.0, 0.0 );       glVertex3f(  1.0,  1.0,  1.0 );       glVertex3f( -1.0,  1.0,  1.0 );       glVertex3f( -1.0, -1.0,  1.0 );       glVertex3f(  1.0, -1.0,  1.0 );glColor3f( 1.0, 1.0, 0.0 );       glVertex3f(  1.0, -1.0, -1.0 );       glVertex3f( -1.0, -1.0, -1.0 );       glVertex3f( -1.0,  1.0, -1.0 );       glVertex3f(  1.0,  1.0, -1.0 );glColor3f( 0.0, 0.0, 1.0 );       glVertex3f( -1.0,  1.0,  1.0 );       glVertex3f( -1.0,  1.0, -1.0 );       glVertex3f( -1.0, -1.0, -1.0 );       glVertex3f( -1.0, -1.0,  1.0 );glColor3f( 1.0, 0.0, 1.0 );       glVertex3f(  1.0,  1.0, -1.0 );       glVertex3f(  1.0,  1.0,  1.0 );       glVertex3f(  1.0, -1.0,  1.0 );       glVertex3f(  1.0, -1.0, -1.0 );       glEnd();       glPopMatrix();       */}

void ConvexDecompositionDemo::displayCallback(void) {	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 	if (m_dynamicsWorld)		m_dynamicsWorld->debugDrawWorld();	renderme();	glFlush();	swapBuffers();}

bool Window::_cmdSwap( co::Command& command ){    const WindowSwapPacket* packet = command.get< WindowSwapPacket >();    LBLOG( LOG_TASKS ) << "TASK swap buffers " << getName() << " " << packet                       << std::endl;    if( getDrawableConfig().doublebuffered )    {        // swap        WindowStatistics stat( Statistic::WINDOW_SWAP, this );        makeCurrent();        swapBuffers();    }    return true;}

//-----------------------------------------------------------------------------void MainWindow::paintGL(){	gr->Clf();	gr->SubPlot(1,1,0);	gr->Rotate(40,60);	gr->Light(true);	gr->AddLight(0,mglPoint(0,0,10),mglPoint(0,0,-1));	gr->Axis();	gr->Box();	gr->FPlot("sin(pi*x)","i2");	gr->FPlot("cos(pi*x)","|");	gr->FSurf("cos(2*pi*(x^2+y^2))");	gr->Finish();	swapBuffers();}

void QGLBlitter::SubWidget::paintGL() {    clear = 2;    if (reinterpret_cast<const QGLBlitter*>(parentWidget())->isPaused()) {// 	if (swapInterval)// 		blitFront();// 	else {        if (!blitted)            blit();        swapBuffers();        blitted = false;// 	}    }}

voidContext::startLoop(){  Info() << "Context initializing renderloop.";  m_loop->initialize(*this);  Info() << "Starting render loop.";  do {    m_loop->render();    swapBuffers();    pollEvents();  } while (!windowShouldClose());  Info() << "Renderloop exited.";}

void GLWidgetRenderer::paintGL(){    DPTR_D(GLWidgetRenderer);    /* we can mix gl and qpainter.     * QPainter painter(this);     * painter.beginNativePainting();     * gl functions...     * painter.endNativePainting();     * swapBuffers();     */    handlePaintEvent();    swapBuffers();    if (d.painter && d.painter->isActive())        d.painter->end();}

void GemWindow::render(void){  if(!makeCurrent()) {    error("unable to switch to current window (do you have one?), cannot render!");    return;  }  if(!pushContext()) {    error("unable to switch to current context, cannot render!");    return;  }  bang();  if(m_buffer==2)    swapBuffers();  popContext();}

void tgSimViewGraphics::displayCallback(){    if (isInitialzed())    {        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);         renderme();        // optional but useful: debug drawing to detect problems        if (m_dynamicsWorld)        {            m_dynamicsWorld->debugDrawWorld();        }        glFlush();        swapBuffers();    }}

void MyWindow::displayFunc() {	glClearColor(1.0f, 1.0f, 1.0f, 0.1f);	glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);	my_cam->update();	glDepthFunc(GL_LESS);		drawBackground();		glDepthRange(0,1000);	drawAxis();	drawCurs();	swapBuffers();	glFlush();}

void View::paintGL(){    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);    glLoadIdentity();    glDisable(GL_LIGHTING);    renderScene();    swapBuffers();    glEnable(GL_LIGHTING);}

void MyWindow::display(){    WindowInertiaCamera::display();    glClearColor(0.4f,0.0f,0.0f,0.0f);    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);    //    // timing for frames    //    //ViewerStates::realtime.update(true);    ViewerStates::fTime += (float)m_realtime.frameDT;    //    // SCENE-LEVEL TEST    //    nvFX::PassInfo pr;    memset(&pr, 0, sizeof(pr));    if(fx_TechScene)    {        int np = fx_TechScene->getNumPasses();        for(int i=0; i<np; i++)        {            nvFX::IPass* scenePass = fx_TechScene->getPass(i, &pr);            if(!pr.bActive)                continue;            if(!scenePass->isValidated())            {                continue;            }            pr.renderingGroup = 0; // set back to 0 before each pass. So no persistent value across passes            scenePass->execute(&pr);            iResolution->updateValue3f((float)m_W, (float)m_H, 0, scenePass);            iGlobalTime->updateValue1f(ViewerStates::fTime, scenePass);            iMouse->updateValue4fv(m_mouse, scenePass);            //iDate       = fx_EffectScene->findUniform("iDate");            //iSampleRate = fx_EffectScene->findUniform("iSampleRate");            switch(pr.renderingMode)            {            default:                break;            }    glUseProgram(0);        }    }    // Draw tweak bars#ifdef USEANTTWEAKBAR    //TwDraw();#endif    swapBuffers();}

void CanvasContext::draw() {    LOG_ALWAYS_FATAL_IF(!mCanvas || mEglSurface == EGL_NO_SURFACE,            "drawRenderNode called on a context with no canvas or surface!");    profiler().markPlaybackStart();    SkRect dirty;    mDamageAccumulator.finish(&dirty);    EGLint width, height;    mEglManager.beginFrame(mEglSurface, &width, &height);    if (width != mCanvas->getViewportWidth() || height != mCanvas->getViewportHeight()) {        mCanvas->setViewport(width, height);        dirty.setEmpty();    } else if (!mDirtyRegionsEnabled || mHaveNewSurface) {        dirty.setEmpty();    } else {        if (!dirty.isEmpty() && !dirty.intersect(0, 0, width, height)) {            ALOGW("Dirty " RECT_STRING " doesn't intersect with 0 0 %d %d ?",                    SK_RECT_ARGS(dirty), width, height);            dirty.setEmpty();        }        profiler().unionDirty(&dirty);    }    status_t status;    if (!dirty.isEmpty()) {        status = mCanvas->prepareDirty(dirty.fLeft, dirty.fTop,                dirty.fRight, dirty.fBottom, mOpaque);    } else {        status = mCanvas->prepare(mOpaque);    }    Rect outBounds;    status |= mCanvas->drawRenderNode(mRootRenderNode.get(), outBounds);    profiler().draw(mCanvas);    mCanvas->finish();    profiler().markPlaybackEnd();    if (status & DrawGlInfo::kStatusDrew) {        swapBuffers();    }    profiler().finishFrame();}

void BenchmarkDemo::displayCallback(void) {#ifdef USE_GRAPHICAL_BENCHMARK	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 		renderme();	//optional but useful: debug drawing to detect problems	if (m_dynamicsWorld)		m_dynamicsWorld->debugDrawWorld();	glFlush();	swapBuffers();#endif //USE_GRAPHICAL_BENCHMARK}

bool Window::_cmdSwap( co::ICommand& cmd ){    co::ObjectICommand command( cmd );    LBLOG( LOG_TASKS ) << "TASK swap buffers " << getName() << " " << command                       << std::endl;    if( getDrawableConfig().doublebuffered )    {        // swap        WindowStatistics stat( Statistic::WINDOW_SWAP, this );        makeCurrent();        swapBuffers();    }    return true;}

void PostComposer::passDistortion() {  writeBuffer->bind();  glClear(GL_COLOR_BUFFER_BIT);  shaderDistortion->bind();  shaderFXAA->transmitUniform("resolution", 1 / widthf, 1 / heightf);  readBuffer->bindAndTransmitTextures(shaderDistortion);  quad->draw(shaderDistortion->attribute("position"));  writeBuffer->unbind();  swapBuffers();}

bool SDLwindow::oneStep(){    if (!initialized){        // init() must be executed in the thread where draw() is called        init();    }    double startT = SDL_GetTicks();    if (!processEvents()) return false;    draw();    swapBuffers();    double dt = SDL_GetTicks() - startT;    if (dt < 1000.0/30){        SDL_Delay(1000.0/30 - dt);    }    return true;}

int main(int argc, char* argv[]){	auto device = RenderDevice::getInstance();		device->init();	device->setQuitOnStart(true);		Text text(30.0f);	text.setString("Random color");		// Create a thread that changes the text color every second	Thread thread([&](void*)	{		while(device->isRunning())		{			text.setColor(Color::Random());			Thread::sleep(Time::seconds(1));		}	});		// Start the thread	thread.start();		while(device->isRunning())	{		device->setTargetScreen(Screen::Top);		device->clear(Color::Black);		device->startFrame();		text.draw();		device->endFrame();				device->setTargetScreen(Screen::Bottom);		device->clear(Color::Black);		device->startFrame();		device->endFrame();				device->swapBuffers();	}		// Wait the thread end	thread.join();		// DON'T FORGET TO CALL THIS OR THE 3DS WILL CRASH AT EXIT	device->destroy();		return 0;}

int main(int argc, char* argv[]){	// Get device singleton instance.	auto device = RenderDevice::getInstance();		device->init();		device->setQuitOnStart(true);		// Create a rectangle shape	RectangleShape rect(100, 60, 100, 100);	// And we set it's color to blue	rect.setColor(Color::Blue);		rect.setOutlineColor(Color::Red);	rect.setOutlineThickness(2);		// Create a line	LineShape line(0, 0, BOTTOM_SCREEN_WIDTH, BOTTOM_SCREEN_HEIGHT);	// And set its color to yellow	line.setColor(Color::Yellow);		// Main loop	while(device->isRunning())	{		device->setTargetScreen(Screen::Top);		device->clear(Color::Black);		device->startFrame();		// Draw the rectangle to top screen		rect.draw();		device->endFrame();				device->setTargetScreen(Screen::Bottom);		device->clear(Color::Black);		device->startFrame();		// Draw a diagonal line on bottom screen		line.draw();		device->endFrame();				device->swapBuffers();	}		// DON'T FORGET TO CALL THIS OR THE 3DS WILL CRASH AT EXIT	device->destroy();		return 0;}

void SerializeDemo::clientMoveAndDisplay(){	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 	//simple dynamics world doesn't handle fixed-time-stepping	float ms = getDeltaTimeMicroseconds();		///step the simulation	if (m_dynamicsWorld)	{		m_dynamicsWorld->stepSimulation(ms / 1000000.f);		#ifdef DESERIALIZE_SOFT_BODIES		if (fSoftBodySolver)            fSoftBodySolver->copyBackToSoftBodies();#endif		m_dynamicsWorld->debugDrawWorld();#ifdef DESERIALIZE_SOFT_BODIES		if (m_dynamicsWorld->getWorldType()==BT_SOFT_RIGID_DYNAMICS_WORLD)		{			//optional but useful: debug drawing			btSoftRigidDynamicsWorld* softWorld = (btSoftRigidDynamicsWorld*)m_dynamicsWorld;			for (  int i=0;i<softWorld->getSoftBodyArray().size();i++)			{				btSoftBody*	psb=(btSoftBody*)softWorld->getSoftBodyArray()[i];				if (softWorld->getDebugDrawer() && !(softWorld->getDebugDrawer()->getDebugMode() & (btIDebugDraw::DBG_DrawWireframe)))				{					btSoftBodyHelpers::DrawFrame(psb,softWorld->getDebugDrawer());					btSoftBodyHelpers::Draw(psb,softWorld->getDebugDrawer(),softWorld->getDrawFlags());				}			}		}#endif //DESERIALIZE_SOFT_BODIES	}			renderme(); 	glFlush();	swapBuffers();}

void Render::paintGL() {	glClear(GL_DEPTH_BUFFER_BIT);	glClear(GL_COLOR_BUFFER_BIT);	glMatrixMode(GL_PROJECTION);	glLoadIdentity();	glFrustum(-getFrustWidth(), getFrustWidth(), -getFrustHeight(), getFrustHeight(), mFrustNear, mFrustFar);	glTranslatef(-mCamPoint.x(),-mCamPoint.y(),-mCamPoint.z());	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	float conv[16];	rotToFloatArray(conv);	glMultMatrixf(conv);	/*float xt = -3;	float xf = 3;	float yf = -3;	float yt = 3;	float z = 0;*/	glColor4f(1, 1, 1, 1);	glLineWidth(10);	glBegin(GL_LINES);	glVertex3f(mCamOldPoint.x(),mCamOldPoint.y(),mCamOldPoint.z());	glVertex3f(mCamOldPoint.x() + mSelectionDir.x(), mCamOldPoint.y() + mSelectionDir.y(), mCamOldPoint.z() + mSelectionDir.z());	glEnd();	glColor4f(1, 0, 0, 1);	glLineWidth(10);	glBegin(GL_LINES);	glVertex3f(mCamOldPoint.x() + mSelectionDir.x(), mCamOldPoint.y() + mSelectionDir.y(), mCamOldPoint.z() + mSelectionDir.z());	glVertex3f(mCamOldPoint.x() + mSelectionDir.x()*2, mCamOldPoint.y() + mSelectionDir.y()*2, mCamOldPoint.z() + mSelectionDir.z()*2);	glEnd();	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);	glColor3f(1,1,1);	mMesh.draw(0,0,0, false, true);/*	glBegin(GL_QUADS);	glVertex3f(xf,yt,z);	glVertex3f(xf,yf,z);	glVertex3f(xt,yf,z);	glVertex3f(xt,yt,z);	glEnd();*/	glFlush();	glFinish();	swapBuffers();}

void ConvexDecompositionDemo::clientMoveAndDisplay(){	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	float dt = getDeltaTimeMicroseconds() * 0.000001f;	m_dynamicsWorld->stepSimulation(dt);	//optional but useful: debug drawing	m_dynamicsWorld->debugDrawWorld();	renderme();	glFlush();	swapBuffers();}